Conveyance seat

ABSTRACT

Improvement is made in a configuration of a movable portion movable to adjust a length of a seat cushion. A vehicle seat includes a seat cushion having a fixed portion and a movable portion movable relative to the fixed portion for adjustment of a length of the seat cushion, and also includes a notch arranged on the movable portion as a movable portion side engagement portion and an engagement plate piece arranged on the fixed portion as a fixed portion side engagement portion. The engagement plate piece is movable between i) a locking position engaged with the notch to bring the movable portion into an unmovable state, and ii) an unlocking position released from the notch to bring the movable portion into a movable state. The movable portion includes a pressing wire to move the engagement plate piece from the locking position to the unlocking position.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the priority benefit ofJapanese Patent Application No. JP 2017-030390, filed Feb. 21, 2017, thecontents being incorporated herein by reference.

BACKGROUND

The present disclosure relates to a conveyance seat and particularlyrelates to a conveyance seat configured for adjustment of a length of aseat cushion by moving a movable portion of the seat cushion.

In some conveyance seats, a length of a seat cushion can be adjusted bymoving a movable portion installed in the seat cushion. For example, avehicle seat described in Japanese Patent Publication JP 2007-118706 A,which includes a moving mechanism in a seat cushion, is capable ofadjusting a front to back length of the seat cushion (a length of thevehicle seat in a front to back direction) by moving the movingmechanism in the front to back direction.

In the configuration having the above-mentioned movable portioninstalled in the seat cushion, a locking mechanism may be provided toprevent the movable portion from being accidentally moved. In such acase, the movable portion and a fixed portion arranged on a seat cushionframe are each provided with an engagement portion for locking. Theengagement portions installed to the movable portion and the fixedportion can be engaged with each other, and their engagement state canbe also released. That is, one engagement portion is moved between aposition of engaging with the other engagement portion (a lockingposition) and a position separated from the other engagement portion (anunlocking position).

In this configuration, when the engagement portion movable between thelocking position and the unlocking position is installed to the movableportion between the movable portion and the fixed portion, the seatneeds to be designed to prevent the above-mentioned engagement portionfrom interfering with its surrounding members during the movement of themovable portion. Further, the above-mentioned engagement portionincludes a mechanism for moving between the locking position and theunlocking position. Thus, the movable portion installed with theabove-mentioned engagement portion increases its number of componentsand weight correspondingly.

SUMMARY

The present disclosure has been implemented in view of the problemsdescribed above, and an embodiment of the present disclosure provides aconveyance seat in which a configuration of a movable portion that ismoved to change a length of a seat cushion is improved.

According to the present disclosure, the above problem can be solved byan embodiment of a conveyance seat including a seat cushion having afixed portion arranged on a seat cushion frame and a movable portionthat is movable relative to the fixed portion for adjustment of a lengthof the seat cushion, in which the conveyance seat further includes amovable portion side engagement portion arranged on the movable portionand fixed relative to the movable portion, a fixed portion sideengagement portion installed on the fixed portion, configured to movebetween a locking position where the fixed portion side engagementportion engages with the movable portion side engagement portion tobring the movable portion into an unmovable state and an unlockingposition where the fixed portion side engagement portion is releasedfrom the movable portion side engagement portion to bring the movableportion into a movable state, and a driving portion, arranged on themovable portion, for moving the fixed portion side engagement portionfrom the locking position to the unlocking position.

The conveyance seat of the present disclosure having the aboveconfiguration includes two engagement portions to restrict the movementof the movable portion. Between them, the engagement portion configuredto move between the locking position and the unlocking position isarranged on the fixed portion. This can prevent the increase of thenumber of components and the weight of the movable portion and improvethe degree of freedom in designing the movable portion.

Further, it is preferred that, in the above-mentioned conveyance seat,respective combinations of the movable portion side engagement portionand the fixed portion side engagement portion are provided at aplurality of positions in a width direction of the conveyance seat. Inthe above configuration, a plurality of mechanisms (that is, thecombinations of the movable portion side engagement portion and thefixed portion side engagement portion) for restricting the movement ofthe movable portion are provided. This enables effective restriction ofthe movement of the movable portion.

Further, it is preferred that, in the above-mentioned conveyance seat,the movable portion includes a rod movable in the front to backdirection to adjust the length of the seat cushion in the front to backdirection of the conveyance seat, the rod is a columnar orcylindrical-shaped member elongated in the front to back direction, andthe movable portion side engagement portion is arranged on the rod. Inthe above configuration, the front to back length of the cushion ischanged by moving the columnar or cylindrical-shaped rod in the front toback direction. Such a configuration enables to adjust the front to backlength of the cushion by using the rod having a general shape.

Further, it is preferred that, in the above-mentioned conveyance seat,the rod includes a first rod and a second rod, which are arrangedseparated from each other in the width direction of the conveyance seat,the first rod is bent towards the second rod in the width direction, andthe second rod is bent towards the first rod in the width direction. Inthe above configuration, the two rods (the first rod and the second rod)are bent towards each other. This provides a reduction in rattling ofthe rods in motion and prevent the rods from interfering with theirsurrounding members.

Further, it is preferred that, in the above-mentioned conveyance seat,the movable portion side engagement portion is a notch formed on anouter peripheral surface of the rod, the notch includes in its interiora first surface and a second surface that face each other in the frontto back direction and are arranged adjacently to each other at a bottomportion of the notch, the first surface extends along a plane having itsnormal direction in the front to back direction, and the second surfaceis inclined to be positioned on an outer side in a radial direction ofthe rod as the second surface goes from an end of the second surfaceadjacent to the first surface toward the other end opposite to the firstsurface. In the above configuration, the notch functioning as themovable portion side engagement portion is formed on the outerperipheral surface of the rod. Further, one surface (the first surface)of the two opposing surfaces included in the notch is orthogonal to thefront to back direction. The other surface (the second surface) isinclined to be positioned on the outer side in the radial direction ofthe rod as separating from the first surface. In such a configuration,the movement of the movable portion can be restricted by a lockingfunction of the engagement portion in a direction from the first surfacetoward the second surface in the front to back direction. On the otherhand, the locking function can be disabled to freely move the movableportion in a direction from the second surface toward the first surface.That is, the above configuration enables to restrict the movement of themovable portion only in one direction in the front to back direction.

Further, it is preferred that, in the above-mentioned conveyance seat,the fixed portion has a guide portion configured to guide the movableportion when the movable portion is moved, and the guide portionincludes the fixed portion side engagement portion. In the aboveconfiguration, providing the guide portion for guiding the movableportion allows the smooth movement of the movable portion. Further,providing the fixed portion side engagement portion to the guide portionenables to simplify the seat configuration as compared with aconfiguration where the guide portion and the fixed portion sideengagement portion are separated.

Further, it is preferred that, in the above-mentioned conveyance seat,the guide portion is elongated along a moving direction of the movableportion. In the above configuration, the guide portion is elongatedalong the moving direction of the movable portion, thus rattling of themovable portion in motion can be effectively suppressed.

Further, it is preferred that, in the above-mentioned conveyance seat,the movable portion is movable in the front to back direction of theconveyance seat to adjust the length of the seat cushion, the conveyanceseat includes an operation portion that is operated to move the fixedportion side engagement portion from the locking position to theunlocking position by the driving portion, and the operation portion,when operated, rotates around a shaft along the width direction of theconveyance seat. In the above configuration, the movable portion ismoved in the front to back direction. Further, in order to move thefixed portion side engagement portion from the locking position to theunlocking position, the operation portion is operated to rotate around ashaft along the width direction of the conveyance seat. That is, theabove configuration allows the operation of the operation portion alongthe moving direction of the movable portion, thereby facilitating theoperation (the operation of the operation portion) for moving themovable portion.

According to the conveyance seat of the present disclosure, twoengagement portions are provided to restrict the movement of the movableportion. Between them, the engagement portion configured to move betweenthe locking position and the unlocking position is arranged on the fixedportion. This can prevent the increase of the number of components andthe weight of the movable portion and improve the degree of freedom indesigning the movable portion. Further, according to the conveyance seatof the present disclosure, providing a plurality of the mechanisms (thatis, the combinations of the movable portion side engagement portion andthe fixed portion side engagement portion) for restricting the movementof the movable portion enables to effectively restrict the movement ofthe movable portion. Further, according to the conveyance seat of thepresent disclosure, the front to back length of the cushion can beadjusted by using a general rod having a columnar or cylindrical shape.Further, according to the conveyance seat of the present disclosure, thetwo rods (the first rod and the second rod) are bent towards each other.This provides reduced rattling of the rods in motion and prevents therods from interfering with their surrounding members. Further, accordingto the conveyance seat of the present disclosure, the notch functioningas the movable portion side engagement portion is formed on the outerperipheral surface of the rod. One surface (the first surface) of thetwo facing surfaces included in the notch is orthogonal to the front toback direction, and the other surface (the second surface) is inclinedto be positioned on the outer side in the radial direction of the rod asseparating from the first surface. This allows restriction of themovement of the movable portion only in one direction (the directionfrom the first surface to the second surface) in the front to backdirection. Further, according to the conveyance seat of the presentdisclosure, the fixed portion side engagement portion is provided to theguide portion for guiding the movable portion. Thus, the movable portioncan be moved smoothly and the seat configuration can be simplified.Further, according to the conveyance seat of the present disclosure, theguide portion is elongated along the moving direction of the movableportion. Thus, rattling of the movable portion in motion can beeffectively suppressed. Further, according to the conveyance seat of thepresent disclosure, the operation portion is operated along the movingdirection of the movable portion for moving the fixed portion sideengagement portion from the locking position to the unlocking position.This can facilitate the operation (the operation of the operationportion) for moving the movable portion.

BRIEF DESCRIPTION OF THE DRAWINGS

Various embodiments of the invention are illustrated in the drawings, inwhich:

FIG. 1 is a schematic side view of a conveyance seat according to anembodiment of the present disclosure;

FIG. 2 is a partial schematic side view of a seat cushion frame of theconveyance seat of FIG. 1, according to an embodiment;

FIG. 3 is a perspective diagram illustrating a movable portion and aguide portion, according to an embodiment;

FIG. 4 is a perspective diagram illustrating the movable portion of FIG.3, where the seat cushion frame is viewed from a front direction,according to an embodiment;

FIG. 5A is a partial schematic diagram illustrating a movement of themovable portion of FIG. 3, where the movable portion is positioned at aback end of a moving range, according to an embodiment;

FIG. 5B is a partial schematic diagram illustrating a movement of themovable portion of FIG. 3, where the movable portion is positioned at afront end of the moving range, according to an embodiment;

FIG. 6 is a bottom view diagram illustrating a locking mechanism, wherea rod and its surroundings are viewed from below, according to anembodiment;

FIG. 7 is a cross-sectional view illustrating configurations of amovable portion side engagement portion and a fixed portion sideengagement portion, according to an embodiment;

FIG. 8A is a partial schematic diagram illustrating the movable portionside engagement portion and the fixed portion side engagement portion ina lock state, according to an embodiment;

FIG. 8B is a partial schematic diagram illustrating the movable portionside engagement portion and the fixed portion side engagement portion inan unlock state, according to an embodiment;

FIG. 9 is a perspective diagram illustrating a lock-releasing mechanism,according to an embodiment;

FIG. 10A is a partial schematic diagram illustrating an operation of thelock-releasing mechanism (Part 1), according to an embodiment;

FIG. 10B is a partial schematic diagram illustrating the operation ofthe lock-releasing mechanism (Part 2), according to an embodiment;

FIG. 10C is a partial schematic diagram illustrating the operation ofthe lock-releasing mechanism (Part 3), according to an embodiment;

FIG. 11 is a side view diagram illustrating an arrangement position ofan operation portion according to a modification, according to anembodiment;

FIG. 12 is a perspective schematic diagram illustrating a lockingmechanism according to a modification, according to an embodiment;

FIG. 13 is a partial schematic diagram illustrating a configurationwhere a pair of right and left locking mechanisms are provided,according to an embodiment; and

FIG. 14 is a schematic diagram illustrating a configuration where a pairof right and left lock-releasing mechanisms are provided, according toan embodiment.

DETAILED DESCRIPTION

An embodiment (the present embodiment) of the present disclosure isdescribed below. A seat equipped in a vehicle (a vehicle seat) is usedas an example to describe a conveyance seat according to the presentembodiment below. However, the present disclosure can be applied to theconveyance seats other than the vehicle seat, for example, seatsequipped in a ship and an airplane.

Note that, in the following description, a “front to back direction”signifies a front to back direction of the vehicle seat and correspondsto an advancing direction of the traveling vehicle. Further, a “seatwidth direction” signifies a width direction of the vehicle seat andcorresponds to a right and left direction as viewed from an occupantsitting on the vehicle seat. Further, an “up and down direction”signifies an up and down direction of the vehicle seat and correspondsto a vertical direction of the vehicle traveling on a horizontalsurface.

Further, a shape, position, attitude, and the like of each portion ofthe seat described below are, unless particularly stated otherwise,conditions of the vehicle seat in a normal state (an initial state ofthe vehicle seat, where each portion of the seat is at an initialposition).

Basic Configuration of Vehicle Seat According to the Present Embodiment

First, a basic configuration of a vehicle seat (hereinafter, referred toas a vehicle seat S) according to the present embodiment is describedwith reference to FIG. 1 and FIG. 2. As shown in FIG. 1, the vehicleseat S includes a seat cushion S1, a seat back S2, and a headrest S3.The seat cushion S1 is configured by mounting a pad material 3 made ofurethane or the like on a seat cushion frame F1 shown in FIG. 2 andcovering the pad material 3 with a cover material 4.

Further, the seat cushion S1 according to the present embodiment isconfigured such that a front and back length (i.e., a length in a frontand back direction) is adjustable by changing a front end position ofthe seat cushion S1. More specifically, the seat cushion S1 includes theabove-mentioned seat cushion frame F1 in its interior. A front sideportion of the seat cushion frame F1 is in a state of being fixedwithout being movable in the front and back direction for adjustment inthe front and back length of the seat cushion S1. That is, the frontside portion of the seat cushion frame F1 is a fixed portion 1 of thepresent embodiment.

On the other hand, the seat cushion S1 includes a movable portion 2movable in the front and back direction in its interior. The movableportion 2 is held by the fixed portion 1 with a portion of the movableportion 2 located at a front end of the seat cushion S1. Then, when themovable portion 2 is moved in the front and back direction relative tothe fixed portion 1 as shown in FIG. 2, the front and back length of theseat cushion S1 is changed as shown in FIG. 1. That is, the movableportion 2 is moved in the front and back direction to change the frontand back length of the seat cushion S1. Note that the front and backdirection corresponds to a moving direction of the movable portion 2.

Movable Portion

Next, a configuration of the movable portion 2 is described withreference to FIG. 3, FIG. 4, FIG. 5A, FIG. 5B, and FIG. 6. Note that, inorder to comprehensively illustrate the movable portion 2 and a guideportion 31 described below, components arranged on the peripheries ofthe movable portion 2 and the guide portion 31 are not shown in FIG. 5Aand FIG. 5B unless they are related to the movable portion 2. Further, aroller portion 11 is shown in FIG. 4 and FIG. 6 in a state in which anouter peripheral portion (a roller body portion) is removed from theroller portion 11.

As shown in FIG. 3, the movable portion 2 includes the roller portion11, a roller support portion 12, and a rod 21. The roller portion 11 islocated at a front end portion of the seat cushion S1, morespecifically, in front of a front end of the seat cushion frame F1.Further, a core material 11 a is arranged in a center portion of theroller portion 11 and the roller portion 11 rotates integrally with thecore material 11 a.

Further, as shown in FIG. 5A and FIG. 5B, the pad material 3 and thecover material 4, located at the front end portion of the seat cushionS1, are wound around an outer peripheral portion of the roller portion11. Then, the rotation of the roller portion 11 causes a change in awinding amount of the pad material 3 and the cover material 4 on theouter peripheral portion of the roller portion 11.

The roller support portions 12 are configured from brackets arrangednear both side ends of the roller portion 11 and rotatably support theroller portion 11 (strictly speaking, end portions of the core material11 a in an axial direction).

The rod 21 is a cylindrical metallic body movable in the front and backdirection to change the front to back length of the seat cushion S1.Note that the rod 21 is formed by a cylindrical pipe in the presentembodiment, however, the present embodiment is not limited thereto. Therod 21 may be formed by a columnar bar, in other embodiments.

The rod 21 is connected to the roller support portion 12. Then, when therod 21 is moved in the front to back direction, the roller portion 11and the roller support portion 12 move integrally with the rod 21. Asshown in FIG. 5A and FIG. 5B, this causes changes in a position of theroller portion 11 in the front to back direction and the winding amountsof the pad material 3 and the cover material 4 on the outer peripheralportion of the roller portion 11. As a result, the front to back lengthof the seat cushion S1 is adjusted.

More specifically, when the rod 21 is at a back end position of itsmoving range, the roller portion 11 and the roller support portion 12are at their initial positions shown in FIG. 5A. In such a state,predetermined amounts of the pad material 3 and the cover material 4 arewound around the outer peripheral portion of the roller portion 11. Notethat the front to back length of the seat cushion S1 when the rollerportion 11 is at the initial position is a normal length (an initialvalue).

Then, when the rod 21 is moved from the back end position to the frontend position of the moving range, the roller portion 11 and the rollersupport portion 12 move forward to a position shown in FIG. 5B(hereinafter, referred to as an extended position). In this operation,the roller portion 11 rotates with the core material 11 a, andaccompanied with this, the pad material 3 and the cover material 4 thatare wound around the outer peripheral portion of the roller portion 11are reeled out. This causes the front end portion of the seat cushion S1to extend and makes the front to back length of the seat cushion S1slightly longer than the normal length.

Conversely, when the rod 21 is moved from the front end position to theback end position of the moving range, the roller portion 11 and theroller support portion 12 retreat toward their initial positions. As aresult, the front to back length of the seat cushion S1 returns to thenormal length.

A configuration of the rod 21 is described in detail. In the presentembodiment, as shown in FIG. 3 and FIG. 6, the rod 21 includes a firstrod 21L and a second rod 21R, which are arranged separated from eachother in the seat width direction. The first rod 21L and the second rod21R are formed in a right and left symmetrical shape relative to acentral position of the seat cushion S1 in the seat width direction, andare also symmetrically arranged in the right to left direction.

Further, a front end portion of the first rod 21L is bent towards thesecond rod 21R in the seat width direction. Similarly, a front endportion of the second rod 21R is bent towards the first rod 21L in theseat width direction.

Specifically, as shown in FIG. 3 and FIG. 4, each of the first rod 21Land the second rod 21R includes a hanging portion 21 a, a horizontalextended portion 21 b, and a front-to-back extended portion 21 c. Thehanging portion 21 a is located at the front end portion of the rod 21and extended downward in an up and down direction. Further, an upper endportion of the hanging portion 21 a is attached to the roller supportportion 12.

The horizontal extended portion 21 b is continued with a lower endportion of the hanging portion 21 a and extended toward inside in theseat width direction. The front-to-back extended portion 21 c iscontinued with an end portion of the horizontal extended portion 21 binside in the seat width direction, and extended backward in the frontto back direction. That is, the rod 21 is bent by substantially 90° at aportion connecting the hanging portion 21 a and the horizontal extendedportion 21 b. The rod 21 is also bent by substantially 90° at a portionconnecting the horizontal extended portion 21 b and the front-to-backextended portion 21 c.

As described above, the first rod 21L and the second rod 21R are bent toshorten a distance between both rods 21 (in other words, in a mannerthat both rods 21 become close to each other). This provides a reductionin rattling of the rods 21 in motion and prevents the rods 21 in motionfrom interfering with their surrounding members.

The guide portion 31 for guiding the movable portion 2 when it is movedis arranged at the front end portion of the seat cushion frame F1 (thatis, the fixed portion 1). As shown in FIG. 3, the guide portion 31 is aresin molded component having a cylinder-like shape and includes a bodyportion 32 and a head portion 33. The body portion 32 is a main bodyportion of the guide portion 31 and is elongated along the front to backdirection (that is, the moving direction of the movable portion 2). Thehead portion 33 is adjacent to a front end portion of the body portion32 and extended in a flange-like shape.

A through hole penetrating through the body portion 32 and the headportion 33 is formed in the guide portion 31. The front-to-back extendedportion 21 c of the rod 21 is inserted into the through hole to befreely advanced and retreated. That is, the rod 21 is moved inside thethrough hole of the guide portion 31 when it is moved in the front toback direction. This allows the rod 21 to appropriately move in thefront to back direction while it is guided by the guide portion 31.Further, the guide portion 31 is elongated along the front to backdirection, thereby enabling it to appropriately guide the rod 21.

Note that the same number of the guide portions 31 as the number of therods 21 are provided, and each of the guide portions 31 is arranged atthe same position as the front-to-back extended portion 21 c of each ofthe rods 21 in the seat width direction. Further, each of the guideportions 31 is inserted into a guide stay 37 of a square-cylindricalshape welded to a lower surface of the seat cushion frame F1. Thus, asshown in FIG. 6, the guide portion 31 is attached to the fixed portion 1via the guide stay 37.

Locking Mechanism

The vehicle seat S includes a locking mechanism that locks theabove-mentioned movable portion 2 to prevent accidental movement. Thelocking mechanism is configured from engagement portions each providedto the fixed portion 1 and the movable portion 2. Further, theengagement portion provided to the fixed portion 1 (a fixed portion sideengagement portion) is configured to be freely engaged and disengagedwith the engagement portion provided to the movable portion 2 (a movableportion side engagement portion). Then, when the fixed portion sideengagement portion is engaged with the movable portion side engagementportion, the movable portion 2 is brought into an immovable state (thatis, a lock state). In other words, a position where the fixed portionside engagement portion is engaged with the movable portion sideengagement portion corresponds to a lock position.

Conversely, when the fixed portion side engagement portion is disengagedfrom the movable portion side engagement portion to release anengagement state of both engagement portions, the movable portion 2 isbrought into a movable state (that is, an unlock state). In other words,a position where the fixed portion side engagement portion is disengagedfrom the movable portion side engagement portion corresponds to anunlock position.

Configurations of the movable portion side engagement portion and thefixed portion side engagement portion are described below with referenceto FIG. 7, FIG. 8A, and FIG. 8B. Note that, in order to comprehensivelyillustrate the configurations of the movable portion side engagementportion and the fixed portion side engagement portion, componentsarranged on the peripheries of these engagement portions (e.g., alock-releasing mechanism) are not shown in FIG. 7, FIG. 8A, and FIG. 8B.

The movable portion side engagement portion is arranged on the rod 21.More specifically, a notch 22 formed on an outer peripheral surface ofthe front-to-back extended portion 21 c of the rod 21 corresponds to themovable portion side engagement portion. As shown in FIG. 7, the notches22, each formed in a substantially V-like shape, are arranged at fixedintervals in the front to back direction. In this manner, positions ofthe notches 22 functioning as the movable portion side engagementportion are fixed relative to the rod 21, and the notches 22 are movedintegrally with the rod 21.

The fixed portion side engagement portion is arranged on the guideportion 31. More specifically, as shown in FIG. 7, each of the headportions 33 in a pair of the right and left guide portions 31 includes aknob portion 34 forming a portion of an outer edge portion of the headportion 33, a biasing spring 35 set within the head portion 33, and anengagement plate piece 36 energized by the biasing spring 35. The knobportion 34 normally protrudes outside in a radial direction of the headportion 33, but can be pressed inside in the radial direction.

In the head portion 33, the engagement plate piece 36 protrudes insidein the radial direction of the head portion 33. Further, the engagementplate piece 36 can be engaged with the notch 22 formed on the rod 21.That is, the engagement plate piece 36 corresponds to the fixed portionside engagement portion and normally stays at a position where theengagement plate piece 36 is engaged with the notch 22, that is, thelock position, as shown in FIG. 8A.

More specifically, an end portion of the engagement plate piece 36,positioned outside in the radial direction of the head portion 33, isinwardly biased in the radial direction by the biasing spring 35. Inthis configuration, when the end portion of the engagement plate piece36, positioned outside in the radial direction of the head portion 33,faces the notch 22 of the rod 21, the engagement plate piece 36 isinserted into the notch 22 to be engaged therewith.

Further, the engagement plate piece 36 can be moved along the radialdirection of the head portion 33 in interlocking with the movement ofthe knob portion 34. Specifically, when the knob portion 34 is inwardlypressed in the radial direction, the biasing spring 35 is compressed(elastically compressed). In this manner, the engagement plate piece 36moves toward outside in the radial direction and is separated from thenotch 22, as shown in FIG. 8B. That is, the engagement plate piece 36reaches a position separated from the notch 22, that is, the unlockposition, when the knob portion 34 is pressed.

As described above, the engagement plate piece 36 can be moved betweenthe lock position shown in FIG. 8A and the unlock position shown in FIG.8B. Then, the engagement plate piece 36 at the lock position is engagedwith the notch 22, thereby restricting the movement of the rod 21 in thefront to back direction. On the other hand, the engagement state of theengagement plate piece 36 and the notch 22 are released when theengagement plate piece 36 is at the unlock position, thereby allowingthe rod 21 to freely move in the front to back direction.

Note that, in the present embodiment, only one locking mechanism isprovided (only on the left side). Specifically, in the presentembodiment, the notch 22 is formed on the first rod 21L positioned onthe left side, and the knob portion 34, the biasing spring 35, and theengagement plate piece 36 are provided to the head portion 33 of theguide portion 31 on the left side. However, the present disclosure isnot limited thereto, and the locking mechanisms (that is, thecombinations of the movable portion side engagement portion and thefixed portion side engagement portion) may be provided at a plurality oflocations. Specifically, a pair of right and left locking mechanisms maybe provided as shown in FIG. 13. FIG. 13 is a sectional viewillustrating a configuration where the pair of right and left lockingmechanisms are provided.

An explanation is now given of the configuration shown in FIG. 13. Thenotches 22 are formed on the front-to-back extended portion 21 c of eachof the first rod 21L and the second rod 21R, and the knob portion 34,the biasing spring 35, and the engagement plate piece 36 are provided toeach of the head portions 33 in a pair of the right and left guideportions 31. Having such a configuration can effectively restrict themovement of the movable portion 2. Note that each portion of the lockingmechanisms (specifically, the notch 22, the knob portion 34, the biasingspring 35, and the engagement plate piece 36) has the same configurationas that described above, and each pair of the portions are symmetricallyconfigured right and left.

Further, in the present embodiment, the member (that is, the engagementplate piece 36) moving between the lock position and the unlock positionis arranged on the fixed portion 1. Providing the member moving betweenthe lock position and the unlock position to the fixed portion 1 cansuppress the increase of the number of components and the weight of themovable portion 2 correspondingly. Further, this also improves thedegree of freedom in designing the movable portion 2.

Further, in the present embodiment, the guide portion 31 has theengagement plate piece 36 functioning as the fixed portion sideengagement portion. In other words, in the present embodiment, a portionfor guiding the movement of the rod 21 and a portion for restricting themovement of the rod 21 are provided to the same member. As a result, inthe present embodiment, the locking mechanism is configured in a moresimplified manner.

Note that, in the present embodiment, a lock function to the movement ofthe rod 21 is effective only in one direction of the movement in thefront to back direction and ineffective in the other direction of themovement. In other words, when the engagement plate piece 36 is at thelock position, the backward movement of the rod 21 is restricted, whileits forward movement of the rod 21 is not restricted. Thus, even whenthe engagement plate piece 36 is at the lock position, the movableportion 2 including the rod 21 can be moved from the initial position tothe extended position.

A configuration of restricting the movement of the rod 21 only in onedirection is described below with reference to FIG. 7. As shown in FIG.7, the notch 22 functioning as the movable portion side engagementportion is formed in a V-like shape. That is, the notch 22 includes inits interior two surfaces facing each other in the front to backdirection. These two surfaces are adjacent to each other at a bottomportion of the notch 22.

Further, a surface located on a back side (hereinafter, referred to as aback side end surface 24) between the above two surfaces corresponds toa first surface and is substantially perpendicular to the front to backdirection as shown in FIG. 7. In other words, the back side end surface24 is arranged along a plane having its normal direction in the front toback direction.

On the other hand, a surface located on a front side (hereinafter,referred to as a front side end surface 23) corresponds to a secondsurface and is formed in an inclined surface as shown in FIG. 7.Strictly speaking, the front side end surface 23 is inclined to bepositioned on the outer side in the radial direction of the rod 21 as itgoes from its back end to front end. The back end of the front side endsurface 23 described herein corresponds to an end of the front side endsurface 23 on a side adjacent to the back side end surface 24. Further,the front end of the front side end surface 23 corresponds to an end ofthe front side end surface 23 at an opposite side to the back side endsurface 24.

According to the notch 22 having a shape described above, even when therod 21 is intended to be moved backward in a situation where theengagement plate piece 36 is at the lock position and engaged with thenotch 22, the engagement plate piece 36 abuts, and thus locked by, theback side end surface 24. As a result, the backward movement of the rod21 is restricted (locked).

In contrast, when the rod 21 is intended to be moved forward in asituation where the engagement plate piece 36 is at the lock positionand engaged with the notch 22, the engagement plate piece 36 moves alongthe inclination direction of the front side end surface 23 without beinglocked, while still abutting the front side end surface 23. Thus, theforward movement of the rod 21 is not restricted (allowed) even thoughthe engagement plate piece 36 is at the lock position.

Lock-Releasing Mechanism

The vehicle seat S includes a lock-releasing mechanism that unlocks themovable portion 2 to extend the front to back length of the seat cushionS1. Specifically, the lock-releasing mechanism includes a drivingportion that moves the engagement plate piece 36 at the lock position tothe unlock position by pressing the knob portion 34 provided to the headportion 33 of the guide portion 31 by the driving portion.

Further, lock-releasing operations of the lock-releasing mechanism(specifically, a series of operations of each portion in thelock-releasing mechanism described below) are initiated by a seatedperson who performs a releasing operation. For this purpose, thelock-releasing mechanism includes an operation portion for receiving areleasing operation performed by the seated person at a predeterminedposition in the vehicle seat S.

A configuration of the lock-releasing mechanism is described below withreference to FIG. 9 and FIG. 10A to FIG. 10C. Note that FIG. 10A to FIG.10C are diagrams illustrating steps of the lock-releasing operations,specifically, operations of each component forming the lock-releasingmechanism in order nearest to a component (specifically, an operationlever 41 described below) operated by the seated person.

As shown in FIG. 9, the lock-releasing mechanism is configured from theoperation lever 41, a connection wire 42, a support bracket 43, asupport shaft 44, a pressing wire 45, and shaft fixing brackets 46 and47. Further, each constituent component of the lock-releasing mechanismis arranged on the movable portion 2.

The operation lever 41, which corresponds to an operation portion, isoperated to move the engagement plate piece 36 from the lock position tothe unlock position by the driving portion. The operation lever 41 is aresin molding component having a substantially triangular shape in sideview, and is attached beneath the front end portion of the seat cushionS1.

More specifically, a rotation shaft 41 a is arranged between thehorizontal extended portions 21 b of the first rod 21L and the secondrod 21R. The rotation shaft 41 a supports the operation lever 41 and hasits axial direction along the seat width direction. Then, the operationlever 41 is attached to each rod 21 with its upper end supported by therotation shaft 41 a.

Further, the operation lever 41 includes a handle on its front lowerportion, and when an occupant as the seated person performs an operationof pulling forward the operation lever 41 with a hand placed on thehandle, the operation lever 41 rotates around the rotation shaft 41 atoward a front side.

The connection wire 42 is a member connected between the operation lever41 and the support bracket 43, and is attached to a back end portion ofthe operation lever 41. Further, the connection wire 42 extends towardan outside in the seat width direction, and then further extends, from amidway position of the connection wire 42, obliquely relative to theseat width direction toward a back side. Further, the connection wire 42moves together with the operation lever 41 when the operation lever 41is rotated. Specifically, as shown in FIG. 10A, when the operation lever41 is rotated toward the front side, one end portion of the connectionwire 42, attached to the operation lever 41, is pulled up.

The support bracket 43 is a metal plate that supports the pressing wire45, and is positioned on a back side of the operation lever 41 and alsoon an outside of the operation lever 41 in the seat width direction. Asshown in FIG. 9 and FIG. 10B, the support bracket 43 includes anoverhang portion 43 b and a support portion 43 c. The overhang portion43 b overhangs toward an inside of the seat width direction. An endportion of the connection wire 42, located at a side opposite to theoperation lever 41, is fixed to the overhang portion 43 b. The supportportion 43 c is continued with the overhang portion 43 b at an outsideof the overhang portion 43 b in the seat width direction, and includes aflat portion extended in a direction intersecting with the overhangingdirection of the overhang portion 43 b. The pressing wire 45 is fixed bywelding to a surface of the support portion 43 c outside in the seatwidth direction.

Further, the support bracket 43 is supported by the support shaft 44extended in the front to back direction, and can be swung to the rightand left with the support shaft 44 as a center. Specifically, the shaftfixing bracket 46 is installed to each of the front-to-back extendedportions 21 c of the first rod 21L and the second rod 21R at a positionin front of the guide portion 31. Further, the shaft fixing bracket 47is installed to each of the front-to-back extended portions 21 c of therods 21 at a position behind the guide portion 31. Then, the supportshaft 44 is installed between the front side shaft fixing bracket 46 andthe back side shaft fixing bracket 47.

The support bracket 43 is swingably supported by a front end portion ofthe support shaft 44. Then, when the connection wire 42 is moved, thesupport bracket 43 swings with the movement of the connection wire 42.Specifically, as shown in FIG. 10B, when the end portion of theconnection wire 42, attached to the operation lever 41, is pulled up,the overhang portion 43 b of the support bracket 43 is also pulled up.This causes the support bracket 43 to swing with the support shaft 44 asa center. The support portion 43 c swings and tilts to the outside inthe seat width direction.

Note that, as shown in FIG. 10B, the support portion 43 c of the supportbracket 43 has a reinforcing bead 43 a that protrudes outwardly in theseat width direction. The reinforcing bead 43 a is formed to improve therigidity of the support bracket 43.

The pressing wire 45 is a wire member supported by the support bracket43, which moves the engagement plate piece 36 from the lock position tothe unlock position. That is, in the present embodiment, the pressingwire 45 functions as the driving portion.

Specifically, as shown in FIG. 9, the pressing wire 45 is located insidethe head portion 33 of the guide portion 31 in the seat width direction,for example, at a position near the knob portion 34. Further, asdescribed above, the pressing wire 45 is held by the support bracket 43.Thus, the pressing wire 45 moves according to the movement of thesupport bracket 43. More specifically, when the support bracket 43 isswung and causes the support portion 43 c to tilt to the outside in theseat width direction, the pressing wire 45 also moves and tilts to theoutside in the seat width direction.

When the pressing wire 45 moves and tilts to the outside in the seatwidth direction, as shown in FIG. 10C, a portion of the pressing wire 45extended in the front to back direction (a pressing portion 45 a) abutsthe knob portion 34 to press the knob portion 34 outside in the seatwidth direction. This compresses the biasing spring 35 set in the headportion 33 of the guide portion 31 to move the engagement plate piece 36outside in the radial direction. As a result, the engagement plate piece36 in a state (that is, in a state at the lock position) of beingengaged with the notch 22 is released from the notch 22 to reach theunlock position.

As described above, the pressing wire 45 as the driving portion pressesthe knob portion 34 provided to the guide portion 31 to move theengagement plate piece 36 from the lock position to the unlock position.

Note that the pressing portion 45 a, a portion of the pressing wire 45,which actually presses the knob portion 34, is configured from a wirehaving a cross section of a circular shape. In other words, the pressingportion 45 a, which has an outer peripheral surface formed in acircumferential surface, presses the knob portion 34 by putting theouter peripheral surface to the knob portion 34. This configurationallows the pressing portion 45 a to appropriately abut the knob portion34. Specifically, for example, when the knob portion 34 is pressed by anedge of a metal bracket, the metal bracket may bite into the knobportion 34. In order to prevent this, the edge needs to be subjected toa rounding processing or a chamfering processing. In contrast, thepressing portion 45 a having a cross section of a circular shape canappropriately abut the knob portion 34 without biting into the knobportion 34 even when the rounding processing or the chamferingprocessing is not performed.

Further, as shown in FIG. 9, the pressing wire 45 is arranged betweenthe shaft fixing brackets 46 and 47 provided on the front and backsides, and thus positioned in the front to back direction by the shaftfixing brackets 46 and 47. Specifically, a front side bent portion 45 bbent in a substantially U-like shape is formed at a front end portion ofthe pressing wire 45. Similarly, a back side bent portion 45 c bent in asubstantially U-like shape is formed at a back end portion of thepressing wire 45.

Then, a portion of the front side bent portion 45 b facing the shaftfixing bracket 46 abuts a back end surface of the shaft fixing bracket46. Similarly, a portion of the back side bent portion 45 c facing theshaft fixing bracket 47 abuts a front end surface of the shaft fixingbracket 47. In this manner, the pressing wire 45 is positioned in thefront to back direction.

Further, the pressing portion 45 a has a sufficient length in the frontto back direction. Specifically, the length of the pressing portion 45 ais slightly longer than a length of the moving range of the rod 21 (inother words, the maximum extension amount of the seat cushion S1). Thus,regardless of any position of the rod 21 in the moving range (in otherwords, any extension amount of the seat cushion S1), the pressingportion 45 a stays near the knob portion 34 to press the knob portion34.

Next, procedures of lock-releasing operations are described as anexample of operations of the lock-releasing mechanism having theabove-described configuration. In the lock-releasing operations, theoccupant as the seated person performs an operation of pulling forwardthe operation lever 41 with the hand placed on the handle formed on thefront surface of the operation lever 41. As shown in FIG. 10A, thiscauses the operation lever 41 to rotate around the rotation shaft 41 atoward the front side. Then, when the operation lever 41 is rotatedtoward the front side, the end portion of the connection wire 42,attached to the operation lever 41, is pulled up.

When the connection wire 42 is moved as described above, the supportbracket 43 swings with the support shaft 44 as a center as shown in FIG.10B. Specifically, the support bracket 43 swings and causes the supportportion 43 c to tilt to the outside in the seat width direction. Then,when the support bracket 43 swings and causes the support portion 43 cto tilt to the outside in the seat width direction, the pressing wire 45also moves and tilts to the outside in the seat width direction.

When the pressing wire 45 moves and tilts to the outside in the seatwidth direction, as shown in FIG. 10C, the pressing portion 45 a of thepressing wire 45 abuts the knob portion 34 to press the knob portion 34outside in the seat width direction. This compresses the biasing spring35 set in the head portion 33 of the guide portion 31 to move theengagement plate piece 36 outside in the radial direction. As a result,the engagement plate piece 36 in a state of being engaged with the notch22 is released from the notch 22 and moved from the lock position to theunlock position.

When the lock is released by the procedures described above, theoccupant can move the movable portion 2 backward to shorten the front toback length of the seat cushion S1. Note that, as described above, inthe present embodiment, the operation lever 41 is pulled forward topress the movable portion 2 backward. That is, as the operation lever 41is configured to rotate in the front to back direction with the rotationshaft 41 a positioned along the seat width direction as a center, theoperation lever 41 moves in substantially the same direction as adirection of the movable portion 2 being pressed backward (a pull-outdirection). Thus, the moving direction of the movable portion 2 and theoperating direction of the operation lever 41 substantially match witheach other. Such a configuration can facilitate the lever operation tomove the movable portion 2.

Note that, in the present embodiment, only one locking mechanism isprovided, thus only one lock-releasing mechanism is providedaccordingly. However, the present disclosure is not limited thereto.When a plurality of the locking mechanisms are provided, the same numberof the lock-releasing mechanisms as that of the locking mechanisms areprovided. For example, when a pair of right and left locking mechanismsare provided as shown in FIG. 13, a pair of right and leftlock-releasing mechanisms are preferably provided as shown in FIG. 14.FIG. 14 is a diagram illustrating a configuration where the pair ofright and left lock-releasing mechanisms are provided.

A configuration shown in FIG. 14 is now described. The components of thelock-releasing mechanisms except for the operation lever 41(specifically, the connection wires 42, the support brackets 43, thesupport shafts 44, the pressing wires 45, and the shaft fixing brackets46 and 47) are symmetrically arranged right and left. Further, thelock-releasing mechanisms are symmetrically configured right and left,where each lock-releasing mechanism has the same configuration as thatdescribed above. Then, when the operation lever 41 is operated, theconstituent components of the lock-releasing mechanisms provided on theright and left sides simultaneously perform the lock-releasingoperations. In this manner, operating one operation lever 41 enables tounlock the pair of right and left lock-releasing mechanisms.

Other Embodiments

In the embodiment described above, the explanation has been mainly givento an example of the configuration of the conveyance seat of the presentdisclosure. However, the above embodiment is merely to facilitateunderstanding of the present disclosure and does not limit the presentdisclosure in any way. That is, the present disclosure can be changedand modified within the scope thereof. Further, it is needless to saythat the present disclosure encompasses equivalents thereof.

Further, in the above embodiment, the operation portion (specifically,the operation lever 41) that is operated for lock-releasing is installedat the lower surface of the front end portion of the seat cushion S1.However, a position of the operation portion is not particularlylimited, and the operation portion may be arranged in front of the seatcushion S1. Alternatively, as shown in FIG. 11, the operation portion(specifically, an operation lever 41 x shown in FIG. 11) may be arrangednear a side of the seat cushion S1.

Further, in the above embodiment, the locking function is only effectivein the backward movement of the movable portion 2, but ineffective inthe forward movement. Specifically, the notch 22 formed on the outerperipheral surface of the rod 21 as the movable portion side engagementportion includes the two surfaces facing each other in the front to backdirection. Further, between the two surfaces, the back side end surface24 is substantially perpendicular to the front to back direction, whilethe front side end surface 23 is inclined to be positioned on the outerside in the radial direction of the rod 21 as it goes from its back endto front end.

However, the present disclosure is not limited to the aboveconfiguration, and the front side end surface of the notch may besubstantially perpendicular to the front to back direction and the backside end surface may be inclined to be positioned on the outer side inthe radial direction of the rod 21 as it goes from its front end to backend. Such a configuration can disable restriction of the backwardmovement of the movable portion 2, while still restricting its forwardmovement. Further, the two surfaces of the notch (the front side endsurface and the back side end surface) may be both substantiallyperpendicular to the front to back direction. Such a configurationenables to effectively exhibit the locking function in the forwardmovement and the backward movement of the movable portion 2.

Further, in the above embodiment, the member, which presses the knobportion 34 to move the engagement plate piece 36 functioning as thefixed portion side engagement portion from the lock position to theunlock position, is configured from the wire. However, the presentdisclosure is not limited thereto, and, for example, a portion of abracket member corresponding to the support bracket 43 may be extendedtoward the knob portion 34, and the knob portion 34 may be pressed by atip portion, of the bracket member, in its extended direction.

Further, in the above embodiment, the operation lever 41 and the supportbracket 43 are connected by the connection wire 42. However, the presentdisclosure is not limited thereto, and, a portion of the support bracket43 (e.g., the overhang portion 43 b) may be extended to the operationlever 41 to directly connect the support bracket 43 with the operationlever 41.

Further, in the above embodiment, the notch 22 formed on the rod 21 andthe engagement plate piece 36 provided to the head portion 33 of theguide portion 31 form the locking mechanism, and the movable portion 2is locked by the engagement plate piece 36 being inserted into the notch22. However, the configuration of the locking mechanism is notparticularly limited, and, for example, the locking mechanism may beconfigured in the same manner as a general locking mechanism used in asliding rail mechanism of a vehicle seat as shown in FIG. 12.

An explanation is now given of the locking mechanism shown in FIG. 12.The locking mechanism is configured from a square cylindrical rod 51corresponding to the rod 21 in the above embodiment, a guide cylinder 52corresponding to the guide portion 31 in the above embodiment, and aswing member 53 formed in a sideways V-like shape in front view. Throughholes 52 a are formed at fixed intervals in the front to back directionon a side wall of the guide cylinder 52 that faces the swing member 53.Further, through holes 51 a are also formed on a side wall of the squarecylindrical rod 51. Then, the square cylindrical rod 51 freely advancesand retreats in the guide cylinder 52. Further, when the squarecylindrical rod 51 is moved relative to the guide cylinder 52 to alignthe through holes 52 a of the guide cylinder 52 and the through holes 51a of the square cylindrical rod 51 in the front to back direction, boththrough holes 51 a and 52 a are in-line (i.e., concentric).

Further, the swing member 53 includes a portion formed in a comb-toothshape at an end portion thereof outside in the seat width direction.Each tooth faces one of the through holes 52 a of the guide cylinder 52and can be freely inserted in and pulled out from the correspondingthrough hole 52 a. Specifically, when the swing member 53 is swung andapproaches the guide cylinder 52, the teeth formed on the end portion ofthe swing member 53 outside in the seat width direction are insertedinto the through holes 52 a. Conversely, when the swing member 53 isswung in a direction separating from the guide cylinder 52, the teethare pulled out from the through holes 52 a.

Then, when the teeth of the swing member 53 are inserted into thethrough holes 52 a of the guide cylinder 52 while the through holes 52 aof the guide cylinder 52 and the through holes 51 a of the squarecylindrical rod 51 are in-line, tip portions of the teeth are alsoinserted into the through holes 51 a of the square cylindrical rod 51.In such a state, a front-back movement of the square cylindrical rod 51can be restricted by the teeth of the swing member 53.

What is claimed is:
 1. A conveyance seat, comprising: a seat cushionhaving i) a fixed portion arranged on a seat cushion frame, and ii) amovable portion that is movable relative to the fixed portion foradjustment of a length of the seat cushion, wherein the conveyance seatfurther includes: a movable portion side engagement portion arranged onthe movable portion and fixed relative to the movable portion; a fixedportion side engagement portion installed on the fixed portion,configured to move between a locking position where the fixed portionside engagement portion engages with the movable portion side engagementportion to bring the movable portion into an unmovable state and anunlocking position where the fixed portion side engagement portion isreleased from the movable portion side engagement portion to bring themovable portion into a movable state; and a driving portion, arranged onthe movable portion, for moving the fixed portion side engagementportion from the locking position to the unlocking position.
 2. Theconveyance seat according to claim 1, wherein respective combinations ofthe movable portion side engagement portion and the fixed portion sideengagement portion are provided at a plurality of positions in a widthdirection of the conveyance seat.
 3. The conveyance seat according toclaim 1, wherein: the movable portion includes a rod movable in thefront to back direction to adjust the length of the seat cushion in thefront to back direction of the conveyance seat; the rod is a columnar orcylindrical-shaped member elongated in the front to back direction; andthe movable portion side engagement portion is arranged on the rod. 4.The conveyance seat according to claim 3, wherein: the rod includes afirst rod and a second rod, which are arranged separated from each otherin a width direction of the conveyance seat; the first rod is benttowards the second rod in the width direction; and the second rod isbent towards the first rod in the width direction.
 5. The conveyanceseat according to claim 3, wherein: the movable portion side engagementportion is a notch formed on an outer peripheral surface of the rod; aninterior of the notch includes a first surface and a second surface thatface each other in the front to back direction and are arrangedadjacently to each other at a bottom portion of the notch; the firstsurface extends along a plane having its normal direction in the frontto back direction; and the second surface is inclined to be positionedon an outer side in a radial direction of the rod as the second surfacegoes from an end of the second surface adjacent to the first surfacetoward the other end opposite to the first surface.
 6. The conveyanceseat according to claim 1, wherein: the fixed portion has a guideportion configured to guide the movable portion when the movable portionis moved; and the guide portion includes the fixed portion sideengagement portion.
 7. The conveyance seat according to claim 6, whereinthe guide portion is elongated along a moving direction of the movableportion.
 8. The conveyance seat according to claim 1, wherein: themovable portion is movable in the front to back direction of theconveyance seat to adjust the length of the seat cushion; the conveyanceseat includes an operation portion that is operated to move the fixedportion side engagement portion from the locking position to theunlocking position by the driving portion; and the operation portion,when operated, rotates around a shaft along a width direction of theconveyance seat.